Weird Problem from 1996 GMC Transmission?

About a month ago, I was making my usual pull to a nearby city approxiamately 75 miles away to do some mowing, I have a 1996 GMC 1500 4x4 automatic. about 50 miles up i started seeing smoke from the rear of the truck, pulled over and transmission fluid poured out from underneath. Spent $200 getting towed back, in the meantime I went and bought a 1997 Ford F-350 which I should have done before anyway. Well with being so busy and all I havent had time until last night to try and find where the leak was coming from. I added 4 quarts of transmission fluid to it, started it up let it idle for abiout 20 minutes everything was fine, took it down the road for about a mile and came back still no leak at all! The transmission housing was dry and all. Has anyone had this experience? The only thing I can figure out is maybe it got hot and justy blew it out, from where I do not know wish i did. Anyway just wondering if anyone else has had the same problem.

I had a car that did that once. Fluid was all over the place. Filled it up later and no more problems. There must be some sort of overflow valve for overheated/overpressurized trannys. Try posing this in the mechanics forum, or just take it to a tranny shop.

We had a U-joint go bad on our 97 2500 and the binding put so much load on the tailshaft that it cracked the housing on the transfer case. The T-case uses ATF also, so check the fluid level in that. There's a big plug about halfway up the back of the case, something like 1"+ on the hex, the part of the plug that shows is very thin, maybe 1/4". If it's low, look very closely at the tailshaft housing just behind where it bolts to the main case casting. There may be a fine crack there. If there is, pull the rear driveshaft and check the front U-joint for freedom of movement. If it's locked up tight that may be the original cause of the problem.